Zig Requires Chilkat v11.0.0+
Zig
OAuth2 Token using IdentityServer4 with Client Credentials
See more OAuth2 Examples
Demonstrates how to get an OAuth2 access token using the client credential flow with IdentityServer4.Chilkat Zig Downloads
const std = @import("std");
const chilkat = @import("chilkat");
pub fn main(init: std.process.Init) !void {
const alloc = init.arena.allocator();
// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
const http = try chilkat.Http.init();
defer http.deinit();
// The first step is to fetch your IdentityServer4's discovery document
// (OpenID Connect defines a discovery mechanism, called OpenID Connect Discovery, where an OpenID server publishes its metadata at a well-known URL,
// typically https://server.com/.well-known/openid-configuration
const resp = try chilkat.HttpResponse.init();
defer resp.deinit();
http.httpNoBody("GET", "https://localhost:5000/.well-known/openid-configuration", resp) catch {
std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
return;
};
if (resp.getStatusCode() != 200) {
std.debug.print("Received response status code {d}\n", .{resp.getStatusCode()});
std.debug.print("Response body containing error text or JSON:\n", .{});
std.debug.print("{s}\n", .{try resp.getBodyStr(alloc)});
return;
}
const json = try chilkat.JsonObject.init();
defer json.deinit();
try json.load(try resp.getBodyStr(alloc));
// We have the discovery document, which contains something like this:
// You can use this online tool to generate parsing code from sample JSON:
// Generate Parsing Code from JSON
// {
// "issuer": "https://localhost:5000",
// "jwks_uri": "https://localhost:5000/.well-known/openid-configuration/jwks",
// "authorization_endpoint": "https://localhost:5000/connect/authorize",
// "token_endpoint": "https://localhost:5000/connect/token",
// "userinfo_endpoint": "https://localhost:5000/connect/userinfo",
// "end_session_endpoint": "https://localhost:5000/connect/endsession",
// "check_session_iframe": "https://localhost:5000/connect/checksession",
// "revocation_endpoint": "https://localhost:5000/connect/revocation",
// "introspection_endpoint": "https://localhost:5000/connect/introspect",
// "frontchannel_logout_supported": true,
// "frontchannel_logout_session_supported": true,
// "backchannel_logout_supported": true,
// "backchannel_logout_session_supported": true,
// "scopes_supported": [
// "openid",
// "profile",
// "email",
// "MyCompany.profile",
// "MyCompany.Identity.WebApi",
// "MyCompany.TriHub.WebApi",
// "offline_access"
// ],
// "claims_supported": [
// "sub",
// "updated_at",
// "locale",
// "zoneinfo",
// "birthdate",
// "gender",
// "website",
// "profile",
// "preferred_username",
// "nickname",
// "middle_name",
// "given_name",
// "family_name",
// "name",
// "picture",
// "email_verified",
// "email",
// "userId",
// "groups",
// "fullname"
// ],
// "grant_types_supported": [
// "authorization_code",
// "client_credentials",
// "refresh_token",
// "implicit",
// "password"
// ],
// "response_types_supported": [
// "code",
// "token",
// "id_token",
// "id_token token",
// "code id_token",
// "code token",
// "code id_token token"
// ],
// "response_modes_supported": [
// "form_post",
// "query",
// "fragment"
// ],
// "token_endpoint_auth_methods_supported": [
// "client_secret_basic",
// "client_secret_post"
// ],
// "subject_types_supported": [
// "public"
// ],
// "id_token_signing_alg_values_supported": [
// "RS256"
// ],
// "code_challenge_methods_supported": [
// "plain",
// "S256"
// ]
// }
//
// The next steps are to (1) get the token_endpoint,
// and (2) verify that the client_credentials grant type is supported.
const token_endpoint = try json.stringOf(alloc, "token_endpoint");
const grant_types = try json.arrayOf("grant_types_supported");
defer grant_types.deinit();
const client_credentials_idx = grant_types.findString("client_credentials", true);
// If clientCredentialsIdx is less then zero (-1) then the "client_credentials" string was not found.
if (client_credentials_idx < 0) {
std.debug.print("The client credentials grant type is not supported.\n", .{});
return;
}
// Request the access token using our Client ID and Client Secret.
// We're going to duplicate this CURL statement:
// curl --request POST \
// --url '<tokenEndpoint>' \
// --header 'content-type: application/x-www-form-urlencoded' \
// --data 'grant_type=client_credentials&client_id=CLIENT_ID&client_secret=CLIENT_SECRET'
const req = try chilkat.HttpRequest.init();
defer req.deinit();
req.setHttpVerb("POST");
req.setContentType("application/x-www-form-urlencoded");
req.addParam("grant_type", "client_credentials");
req.addParam("client_id", "CLIENT_ID");
req.addParam("client_secret", "CLIENT_SECRET");
req.setHttpVerb("POST");
http.httpReq(token_endpoint, req, resp) catch {
std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
return;
};
// Make sure we got a 200 response status code, otherwise it's an error.
if (resp.getStatusCode() != 200) {
std.debug.print("POST to token endpoint failed.\n", .{});
std.debug.print("Received response status code {d}\n", .{resp.getStatusCode()});
std.debug.print("Response body containing error text or JSON:\n", .{});
std.debug.print("{s}\n", .{try resp.getBodyStr(alloc)});
return;
}
try json.load(try resp.getBodyStr(alloc));
// Our JSON response should contain this:
// {
// "access_token":"eyJz93a...k4laUWw",
// "token_type":"Bearer",
// "expires_in":86400
// }
// Get the access token:
_ = try json.stringOf(alloc, "access_token");
// The access token is what gets added to "Authorization: Bearer <access_token>"
// for the subsequent REST API calls..
}